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Tuesday, March 24, 2009

In Over My Head

This column was originally written in July 2008.

Summer is in full force in southwest Georgia and afternoons outside can be sweltering. The heat can be oppressive, even many snakes and lizards choose to spend their days in underground burrows, where it may be cooler.

So, I didn’t hesitate for long when another graduate student at the Center offered me the opportunity to accompany him on a turtle surveying trip in nearby Spring Creek. Now, I should tell you that turtle surveys are basically an excuse to go snorkeling and that’s exactly what I feel like doing after sweating under the sun. The only setback was that due to a 2:00 p.m. meeting of mine, we’d have to get in the water at about 10:00 a.m., a few hours earlier than normal surveys. No problem, I thought.

I met Sean and Brent at the lab and we got our gear together. Did I want to bring my wetsuit they asked? Now, I’m a native New Yorker and I pride myself at not complaining about the cold, at least not in front of any of my friends from Georgia. So, I quickly explained that I wouldn’t need my insulated wetsuit, I mean, how cold could a South Georgia creek be? Brent and Sean exchanged a look.

“Okay, I’ll bring it…just in case.”

This proved to be a wise decision.

After a short drive we unloaded our canoe and stepped into the water. Brent uttered a high-pitched squeal as it lapped at his calves. It’s cold, his shriek indicated.

Our plan was to take a short canoe trip to one of Sean’s study sites where we would unload our gear and snorkel 500 meters downstream (a trip of about an hour and a half). Once we reached the 500 meter mark, we’d turn around and snorkel back to the canoe. Sean’s research aims to determine how river turtle populations are influenced by surrounding land use. He’s sampling turtles by trapping and by hand capture (via snorkeling) in relatively pristine creeks surrounded by forests and in areas that are more impacted by land uses such as agriculture. By comparing what he finds in the different areas, he’ll be able to see if and how turtles are affected.

It was a short trip to our starting point and a single foot in the water quickly convinced me that I would put on my wetsuit after all. The rest of my gear included flippers, gloves and a snorkel and goggles. Our job was to keep our eyes peeled for any turtle of any size. This is trickier than it sounds, different species prefer different habitats and vary widely in color and patterning, once we establish a search image in our head, it’s sometimes hard to see anything else.

After we spotted a turtle, we needed to catch it so Sean could measure it and make marks in their shell so he could recognize it if it was captured again. Although turtles have a reputation for being slow, a few minutes trying to swim after one will quickly dispel that notion. Our flippers evened the playing field somewhat.

I braced myself and submerged, inhaling sharply as the cold water reached various portions of my body. After a few moments of searching through a maze of underwater roots near the shoreline, I spotted a loggerhead musk turtle (on right). It was perched on one of the roots, craning its long neck towards me. This small, brown turtle is often caught by fishermen; it’s not a picky eater and loves to feed on carrion and small invertebrates, including worms. I quickly grabbed him, careful to keep my fingers away from its jaws. Although small, they have a legendary bite. I handed the turtle off to Sean for him to process and dove underwater. Sean's semi-aquatic, mobile, turtle-processing lab is demonstrated below.

After about 20 minutes, I started to feel a tingling sensation in my foot and I assumed that the tight flippers had started to cut off my circulation. No problem I figured, I’d just periodically take off the flippers and allow the blood to flow back into my foot.

It wasn’t long before Brent started to find turtles as well, quickly bringing a yellow-bellied slider and river cooter back to Sean. The slider is an abundant southeastern species and it’s a habitat generalist, meaning it’s found in a wide variety of wetlands from creeks to small temporary ponds. The cooter, on the other hand, is rarely found in areas other than riverine systems. When it comes to diet, the slider isn’t picky there either, eating everything it can fit in its jaws. This species is the turtle most often caught in traps baited with sardines. The more vegetarian cooter, however, is not as vulnerable.

The turtles tended to prefer one of two kinds of habitat. We found sliders and cooters in brushy areas, where the current had consolidated branches and other riprap (these areas also held largemouth bass and big bream) and we also found lots of turtles hiding under submerged logs in deep holes. These logs are considered deadhead logs, left over from the days when the forests were intensively harvested and the wood was floated downstream. Left behind for decades, they are now excellent turtle hiding spots.

One of the more exciting finds was an adult female Barbour’s map turtle. Map turtles are often restricted to single river systems, for example, the Barbour’s map turtle can only be found in drainages associated with the Apalachicola. Other species of map turtles can be found in other rivers. Males and females of this unusual species are strikingly different. Females can be three times the size of tiny males and have huge, broad jaws that they use to crush the mussels they eat.

We hit the halfway point right on time. As we paused before turning around I noticed that the tingling sensation had spread to my hands as well. In the excitement of swimming in the creek and catching turtles I didn’t notice the cold. The blood had left my extremities to keep my core warm, and as a result my hands and feet had gone to sleep. I looked for a sunlit spot on the bank and I began to shake my hands around wildly to get the blood flowing again. Brent and Sean also began to feel the effects; our teeth chattered when we spoke to each other and our hands shook mightily when we tried to help Sean write down data. Without compromising our survey, we tried to cover the water back to the canoe as quickly as possible. We continued to find turtles, but we did so reluctantly, and they were processed as quickly as possible.

When all was said and done we had captured twelve turtles of four species, not a bad haul and important data for Sean’s project. I’ll help again, but I’ll have to make sure that we do so in the afternoon when the water’s warm. I suppose there was at least one upside; perhaps the cold water is what deterred any curious alligators from taking a closer look.